1. Field of the Invention
The invention relates to the field of locks with keys. More particularly, the invention relates to a method of coding a key and a female lock part.
2. Discussion of the Prior Art
In a trapped key interlocking system, the lock stamp or female lock part is built into the lock of the trapped key interlocking system and is therefore an integral component of the system, whereby a key is needed to open the lock and thereby the female lock part. The individual locks are provided with a unique coding between the female lock part and the key, so that it is only possible to operate the lock with a key having the matching code. Normally, the key meshes into the female lock part of the lock and thus creates a form-fitting unit. The female lock part itself works, for example, together with a blocking arrangement of the tumbler, or via an integrated square edge or something similar, for example, with an electrical switch.
An example of the prior art is shown in FIG. 1. The coding comprises a combination of pins and boreholes. The key has a number of boreholes in a given arrangement, and the lock stamp is provided with an identical number of pins in the same arrangement as that of the key, which, when the codes match, can mesh into the boreholes of the key. The key can then be inserted far enough into the lock to operate the lock. It is not possible to operate the lock, if the hole and pin patterns do not match.
The prior art also teaches that, instead of pins and boreholes, milled letters or combinations of letters can be provided as key coding. Milled or cast contours are also used.
Characteristic for the prior art and the conventional codings is that the codings must be manufactured separately for the keys and the lock stamps. This means that the key is coded, for example, by machining the bores, and that the female lock part is made to match the key, by machining the bores and pressing in the pins.
It is obvious that the manufacturing these known codings is costly and that the number of codings is limited.